This invention relates to suction catheter systems with suction control valves and especially those used in medical applications. Suction catheters are used to remove secretions from a patient's airway and catheters fall into two categories of single use disposable: “open” style catheters and the newer type “closed” systems manufactured by Ballard Medical Inc. and SIMS Portex.
“Open” style catheters typically use a normally open suction control valve such as those described in U.S. Pat. No. 4,534,542 to Russo. The “closed” tracheal suction systems typically use a normally closed suction control valve as described in U.S. Pat. No. 4,569,344 to Palmer, U.S. Pat. No. 4,696,296 also to Palmer, and U.S. Pat. No. 5,073,164 to Hollister. The closed systems usually comprise a frontal connector attachable to a ventilator and the patient's endotracheal tube along with a protective sleeved suction catheter and a normally closed suction control valve. The valve must be normally closed to prevent the loss of administered ventilation when the patient is not being suctioned since the closed system is left attached to the patient and the breathing circuit at all times.
The normally closed valves described in the above patents to Palmer and Hollister are actually in commercial use as part of the Ballard Medical Trach-Care® product and the SIMS Portex Steri-Cath®, and they suffer from several limitations that impact their clinical efficacy and their low suction efficiency. As noted, the valves used in both the Ballard Medical and SIMS Portex devices are 100% obstructed when they are positioned in their non-activated, non-suction applied mode. However, they remain in a partially blocked or partially obstructed flow path position when they are activated in their suction applied mode. This means that suction levels have to be set exceedingly high in order to equal the suction efficiency of the open straight through flow paths of the open style catheters. Actual suction levels in an open to style catheter are usually set at a clinically documented low suction level of about 125 mm Hg and will efficiently remove viscous secretions with little mucosal tissue grab and trauma at that level.
By comparison, actual levels in some closed systems have to be set at 300 mm Hg to approach the suction efficiency of the open style devices. Even at that level, the closed devices sometimes have difficulty removing viscous secretions due to the obstructive, restrictive flow path design of their normally closed valves that also decreases airflow at the distal tip of the catheter. Also, since the Palmer/Ballard Medical valve type has a spring action biased sealing member acting on a valve seat, the seating surface is more prone to being clogged by viscous secretions especially if the valve is not flushed well after use. Clogging of the valve seat may leave the valve partially open such that the valve may have a slow leakage of ventilated gases since it may not seal 100% closed. In addition, the Palmer/Ballard Medical valve type has many cooperating parts requiring more expensive manufacturing in assembly time and labor.
Towards this end, a Suction System with High Efficiency Suction Control Valve has been conceived to provide a normally closed suction control valve which is non-obstructive to both fluid and airflow in its suction applied mode and will only require the low 125 mm Hg safe level of suction.
Further, closed tracheal suction devices such as the Ballard Trach-to Care® and SIMS Steri-Cath® are being used for repeated suctioning and secretion removal procedures, and these devices can stay connected to a patient's respiratory system for up to 72 hours or 3 days. Ballard Medical has recently commercially introduced a 72 hour product (Trach-Care 72) which is the commercial embodiment of U.S. Pat. No. 6,227,200 issued to Crump et al and assigned to Ballard Medical Products which references many of the prior art patents. However, this new Trach-Care® 72 still uses the same obstructive suction control valve used in the original Trach-Care®. Viscous secretions, which may tend to partially accumulate in the frontal connector portion of closed tracheal suction devices, can easily be re-introduced by the catheter during subsequent suctioning procedures, which may cause VAP (ventilator-associated pneumonia). Complete removal of secretions throughout the system is of paramount importance. It would be ideal to provide a high efficiency suction control valve that could be utilized as part of a closed tracheal suction system which completely isolates the catheter when not in use and which thoroughly and effectively cleans all secretions after use and also prevents the accumulation of secretions within the system especially within the connector. Thus, there is a need for a catheter apparatus that will solve all the aforementioned problems.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.